Comparative Study of Oil Quality and Aroma Profiles from Tunisian Olive Cultivars Growing in Saharian Oasis Using Chemometric Analysis

Aroma profile, oxidative stability and quality parameters of virgin olive oil from four cultivars (Chemlali, Chetoui, Koroneiki and Rjim), grown in Rjim Maatoug oasis in southern of Tunisia, were studied for the first time. The olive oil samples were obtained during maturation from a crop season (2012-2013). The results showed the quality parameters, i.e., free fatty acid, UV absorbance at 232 and 270 nm, increases during maturation exceeding the upper limit established by the IOOC norm. Chlorophyll and carotenoid pigments tended to decrease during ripening stages. The trend of oxidative stability, total phenols and O-diphenols exhibited a reduction of antioxidant activity at more advanced stages of maturity. The marks achieved showed that oil quality degradation is due to the great drought of climate: high temperature, high light intensity and low rainfall. Studied aroma profiles of cultivars were also influenced by severe climatic conditions. Twenty-four compounds were characterized, representing 94.8-99.8% of the total volatiles. In all samples, a strong decrease was observed in aldehydes compounds

Comparative Study of Oil Quality and Aroma Profiles from Tunisian Olive Cultivars Growing in Saharian Oasis Using Chemometric Analysis

Aroma profile, oxidative stability and quality parameters of virgin olive oil from four cultivars (Chemlali, Chetoui, Koroneiki and Rjim), grown in Rjim Maatoug oasis in southern of Tunisia, were studied for the first time. The olive oil samples were obtained during maturation from a crop season (2012-2013). The results showed the quality parameters, i.e., free fatty acid, UV absorbance at 232 and 270 nm, increases during maturation exceeding the upper limit established by the IOOC norm. Chlorophyll and carotenoid pigments tended to decrease during ripening stages. The trend of oxidative stability, total phenols and O-diphenols exhibited a reduction of antioxidant activity at more advanced stages of maturity. The marks achieved showed that oil quality degradation is due to the great drought of climate: high temperature, high light intensity and low rainfall. Studied aroma profiles of cultivars were also influenced by severe climatic conditions. Twenty-four compounds were characterized, representing 94.8-99.8% of the total volatiles. In all samples, a strong decrease was observed in aldehydes compounds

Impact of Wastewater Spreading on Properties of Tunisian Soil under Arid Climate

The environmental impacts of irrigating an olive field with olive mill wastewater (OMW) and treated wastewater (TWW) on soil properties were investigated. The effect of different irrigation treatments of OMW (50 m3 ha−1, 100 m3 ha−1, and 200 m3 ha−1) and TWW at different soil depths was studied. The obtained findings revealed that TWW application augmented soil pH; EC values; and P, K and Ca contents in all soil layers. However, Mg and Na concentrations, as well as organic matter content (OM), were proven to decrease with TWW irrigation throughout the experiment. Whereas soil adjusted with OMW showed a decrease in K, Ca, Mg and Na contents with soil depth, a significant increase was observed with the increase in applied OMW dose. On the other hand, total phenols and OM content increased significantly with the rise in OMW levels in all the investigated layers compared to the control sample

Impact of Wastewater Spreading on Properties of Tunisian Soil under Arid Climate

The environmental impacts of irrigating an olive field with olive mill wastewater (OMW) and treated wastewater (TWW) on soil properties were investigated. The effect of different irrigation treatments of OMW (50 m3 ha−1, 100 m3 ha−1, and 200 m3 ha−1) and TWW at different soil depths was studied. The obtained findings revealed that TWW application augmented soil pH; EC values; and P, K and Ca contents in all soil layers. However, Mg and Na concentrations, as well as organic matter content (OM), were proven to decrease with TWW irrigation throughout the experiment. Whereas soil adjusted with OMW showed a decrease in K, Ca, Mg and Na contents with soil depth, a significant increase was observed with the increase in applied OMW dose. On the other hand, total phenols and OM content increased significantly with the rise in OMW levels in all the investigated layers compared to the control sample

Soil fluoride spiking effects on olive trees (Olea europaea L. cv. Chemlali)

International audienceA pot experiment under open air conditions was carried out to investigate the uptake, accumulation and toxicity effects of fluoride in olive trees (Olea europaea L.) grown in a soil spiked with inorganic sodium fluoride (NaF). Six different levels (0, 20, 40, 60, 80 and 100 mM NaF) of soil spiking were applied through NaF to irrigation water. At the end of the experiment, total fluoride content in soil was 20 and 1770 mg F kg−1 soil in control and 100 mM NaF treatments, respectively. The comparative distribution of fluoride partitioning among the different olive tree parts showed that the roots accumulated the most fluoride and olive fruits were minimally affected by soil NaF spiking as they had the lowest fluoride content. In fact, total fluoride concentration varied between 12 and 1070 µg F g−1 in roots, between 9 and 570 µg F g−1 in shoots, between 12 and 290 µg F g−1 in leaves, and between 10 and 29 µg F g−1 in fruits, respectively for control and 100 mM NaF treatments. Indeed, the fluoride accumulation pattern showed the following distribution: roots>shoots>leaves>fruits. On the other hand, fluoride toxicity symptoms such as leaf necrosis and leaf drop appeared only in highly spiked soils (60, 80 and 100 mM NaF)

Exogenous proline enhances growth, mineral uptake, antioxidant defense, and reduces cadmium-induced oxidative damage in young date palm (Phoenix dactylifera L.)

International audienceThe aim of this study was to investigate the effects of cadmium stress on growth and physiological traits in young date palms and to evaluate the role of exogenous proline in cadmium stress alleviation. Two-year-old date palm plants were subjected for five months to different cadmium stress levels (10 and 30 mg CdCl2 kg−1 soil) supplied or not with exogenous proline (20 mM) through irrigation water. Cadmium stress caused a decline in growth, macronutrient contents (Ca2+, Mg2+, and K+), membrane stability index (MSI), starch content and guaiacol peroxidase (POD) activity. In contrast, an increase of H2O2, soluble sugar, ascorbate peroxidase (APX) activity as well as total polyphenols was observed. Interestingly, exogenous proline effectively mitigated the adverse effects of cadmium on young date palms. Indeed, Cd accumulation was decreased and antioxidant defense systems were significantly (p ≤ 0.05) activated in date palm leaves and roots. Consequently, growth and mineral nutrition were enhanced when proline was added to Cd stressed plant

Physiological responses of date palm (Phoenix dactylifera L) exposed to air and soil pollution near the industrial complex in Sfax, Tunisia

International audienceThis study aims to evaluate the impact of complex air and soil pollutions on date palm plants (Phoenix dactylifera), one of the most important commercially valuable crops in Tunisia. These field experiments were performed in the vicinity of the industrial complex in the south of Tunisia (Sfax) for the polluted samples and in unpolluted areas for control date palm plants. Several biomarkers were studied belonging mainly to the antioxidant system like enzymes or antioxidant compounds.Mains results indicate that air and sol pollution induced an oxidative stress as demonstrated by an increase in the rate of hydrogen peroxide (H2O2) production, electrolyte leakage and lipid peroxidation in all plant parts. This stress affects chlorophyll and carotenoid contents of leaves. Additionally, the activities of enzymes involved in reactive oxygen species (ROS) detoxification were affected. Air and soil pollution induce an increase in the activities of ascorbate peroxidase (APX), glutathione peroxidase (GPX), superoxide dismutase (SOD) and catalase (CAT). Moreover, in polluted date palm plants the contents of antioxidant molecules like polyphenols and proline increase strongly, this is consistent with the role of these potent antioxidants in scavenging ROS. The present study evidenced the deleterious effects of industrial activity on antioxidative defense system of Phoenix dactylifera, an important crop species spreading in arid region of Tunisia

Impact of proline application on cadmium accumulation, mineral nutrition and enzymatic antioxidant defense system of Olea europaea L. cv Chemlali exposed to cadmium stress

International audienceProline plays an important role in plant response to various environmental stresses. However, its involvement in mitigation of heavy metal stress in plants remains elusive. In this study, we examined the effectiveness of exogenous proline (10 and 20mM) in alleviating cadmium induced inhibitory effects in young olive plants (Olea europaea L. cv. Chemlali) exposed to two Cd levels (10 and 30mg CdCl2kg(-1) soil). The Cd treatment induced substantial accumulation of Cd in both root and leaf tissues and a decrease in gas exchange, photosynthetic pigments contents, uptake of essential elements (Ca, Mg and K) and plant biomass. Furthermore, an elevation of antioxidant enzymes activities (superoxide dismutase, catalase, glutathione peroxydase) and proline content in association with relatively high amounts of hydrogen peroxide, thiobarbituric acid reactive substances and electrolyte leakage were observed. Interestingly, the application of exogenous proline alleviated the oxidative damage induced by Cd accumulation. In fact, Cd-stressed olive plants treated with proline showed an increase of antioxidant enzymes activities, photosynthetic activity, nutritional status, plant growth and oil content of olive fruit. Generally, it seems that proline supplementation alleviated the deleterious effects of young olive plants exposed to Cd stres